1/10/2007

Last year was the warmest on record in the continental United States, the federal government reported Tuesday, attributing the temperatures to the natural El Nino cycle as well as to long-term warming linked to human emissions of greenhouse gases.The findings are preliminary, and a final review later this year could still put 2006 just below the previous record set in 1998, the National Climatic Data Center reported. But in any case, the two years are pretty much a tie in terms of hot ones since recordkeeping began in 1880.Both years averaged around 55 degrees Fahrenheit — 2.2 degrees above the 20th century mean.